National Science Foundation     |     Directorate for Engineering  (ENG)
Division of Chemical, Bioengineering, Environmental, & Transport Systems  (CBET)
CBET Research Highlights 
Notable Accomplishments from CBET Awards
7643 - Part A - Improving Crude Oil Cleanup
Behzad Mortazavi  -  University of Alabama Tuscaloosa

Outcome or Accomplishment:  In response to the Gulf oil spill, researchers at the University of Alabama have shown that the degradation of crude oil by microbes can be significantly enhanced by the addition of naturally occurring marine organic matter.

Behzad Mortazavi Image 1
- Figure 1.  Tar balls at an Alabama marsh ecosystem.
Credit for Images 1, 2 and 3:  Patricia Sobecky, University of Alabama

Behzad Mortazavi Image 2
- Figure 2.  A marsh in Albama impacted by the oil spill.

Behzad Mortazavi Image 3
- Figure 3.  Oil sheen observed off the coast of Alabama following the Deepwater Horizon explosion.

Behzad Mortazavi Image 4
- Figure 4.  Tar balls at a beach in Alabama.
Credit for Image 4:  Behzad Mortazavi, University of Alabama

Impact:  Oil spills resulting from accidents or natural disasters contaminate land, lakes, and the coastal sea.  Accelerating the breakdown of crude oil is important because toxicity can persist for long time periods in contaminated beaches or salt marshes.  Mechanical removal of contaminated sediments on the beach and marshes can have detrimental effects, for example, on nesting sea turtles or marsh structure.  Bioremediation (the use of naturally occurring microbes to breakdown contaminated soils and water) is less destructive.  Accelerating natural biodegradation processes help to preserve vital environments.

Explanation/background:  Over time, microbes break down crude oil.  However, their activity can be slowed by the scarcity of essential nutrients.  Crude oil washing ashore can persist for decades in contaminated shorelines.  Applications of nitrogen and phosphorus fertilizers to contaminated areas have resulted in faster crude oil degradation.  Applying large quantities of fertilizers in coastal ecosystems, however, can have undesirable effects (ex. algae blooms).  Improvements in technologies that can alleviate nutrient limitation without adversely impacting an ecosystem are essential to faster recovery following crude oil contamination.
The research team has monitored the seasonal abundances of hydrocarbon degrading bacteria at a salt marsh site in Alabama contaminated by crude oil following the Deepwater Horizon explosion.  In addition to finding an increase in bacteria there was an increase in hydrocarbon degradation genes.  Within months of the impact, hydrocarbon concentrations decreased to undetectable values.  The increased population and activity of the bacteria studied indicated that in situbioremediation was taking place at the salt marsh.  Experiments in the laboratory showed that the degradation of hydrocarbons is increased by as much as 3 times in response to the addition of nutrients.  In contrast to previous work where nitrogen and phosphorus fertilizers were used to accelerate biodegradation, the team relied on organic matter from fish and vegetation present at the site as the nutrient source to accelerate biodegradation.

CBET Research Highlight - Part B - Engineering Technical Information

7643 - Accelerating the Bioremediation of Crude Oil

Behzad Mortazavi  -  University of Alabama Tuscaloosa

Background:  Oil spills resulting from accidents or natural disasters contaminate land, lakes, and the coastal sea.  The toxicity from crude oil not only harms birds, mammals, fish, shellfish and humans but can also result in widespread economic impacts.  The impact of oil spills was recently highlighted by the explosion of the Deepwater Horizon oil platform in the Gulf of Mexico that resulted in the largest crude oil spill to date.  A fraction of the released crude oil washed ashore and impacted beaches and marshes along the northeastern Gulf of Mexico.  Marshes serve as nursery grounds for many of the commercially important species and exposure to oil constituents even at very low concentrations can impact these organisms.  The options for cleaning the marsh are limited because physical removal of tar balls or contaminated sediments can further damage the marsh.  Bioremediation, the degradation of oil by the microbial community naturally present in the marsh, is often the technique of choice for marsh clean up.
An interdisciplinary team at the University of Alabama has characterized the microbial community capable of hydrocarbon degradation, and evaluated techniques for accelerating degradation rates in impacted coastal ecosystems.  Concentrations of hydrocarbon, seasonal abundances and community structure of the indigenous microbes capable of degrading hydrocarbons were determined at the intertidal zone and included marshes, creek banks, beaches and seagrass beds.  Mesocosm experiments were used to determine means of accelerating the rate of hydrocarbon degradation.  The mesocosms serve as the first stage for formulating a strategy for accelerating the bioremediation of crude oil in such systems.

Results:  The microbial community structure and function of the indigenous hydrocarbon-degrading microbial population significantly changed following contamination by crude oil.  Functional genes involved in hydrocarbon degradation were enriched in oil-contaminated sediments and declined significantly as hydrocarbon concentrations decreased.  The increase in the naturally-occurring microbial populations containing known hydrocarbon-degrading bacteria and the subsequent increase in hydrocarbon degradation functional genes indicated that in situ bioremediation contributed to hydrocarbon degradation at the contaminated sites.  The rate of hydrocarbon degradation was significantly enhanced after supplying the sediments with marine organic matter from fish and marsh vegetation to alleviate nutrient limitation.  The addition of material at low concentrations in a form suitable for use by the indigenous microbial community provides an alternative approach to application of large quantities of nitrogen and phosphorus fertilizers for enhancing bioremediation in the coastal region.

CBET Strategic Outcome Goals include:
- 1Discovery:  The research program is focused on transforming the knowledge base of US researchers on the structure of the hydrocarbon degrading microbial community capable of in the coastal region and to use a novel approach that relies on insitu material for enhancing bioremediation of crude oil.

- 2Learning:  In terms of the goals for an inclusive science and engineering workforce, this project has brought together an international post doctoral scientist as well as several graduate students and undergraduates.  This group of researchers, through collaborative work, obtained a broad knowledge of the impact of oil spills on coastal ecosystems.

Transformative Research:  This NSF-funded research is transformative in the way that the advanced techniques in microbial genomics were interfaced with field and experimental efforts to arrive at a better understanding of the role of microbial community in bioremediation of crude oil and enhancements in the rate of crude oil degradation in coastal ecosystems.

Intellectual Merit:  This research program has provided scientists with (i) a detailed understanding of the response of the microbial community in a marsh ecosystem to an oil spill, and (ii) potential improvements in remediation technology through the use of indigenous materials that significantly enhance bioremediation.  The information gained from this proposal will provide the research community with potential mitigation strategies in case of future coastal oil spills.

Broader Impacts of this research include:
- 1Benefits to society: Coastal ecosystems and specifically marshes are critical habitats for the development of many of the commercially important fisheries.  Determining the impact of oil spills and improving techniques for remediation of impacted ecosystems provides invaluable benefits to the society.
- 2Participation of underrepresented groups:  The project broadens participation by supporting investigators in an EPSCOR state (Alabama) and allows graduate and undergraduate students and a post-doctoral scientist to participate in state-of-the-art research in molecular biology and biogeochemistry.
- 3Teaching, Training, and Learning: This research is providing information on the microbial community structure at a marsh ecosystem impacted by an oil speed as well as insights into means of accelerating the recovery following contamination.  This information is incorporated into graduate and undergraduate courses.  Graduate students involved in this project are being trained in the latest technologies available today.
- 4Results disseminated broadly to enhance scientific and technological understanding:  Publications in scientific journals are the means by which research results are being disseminated.  In addition, the investigators have distributed information gained from this project in formats suitable for Newspapers within the State of Alabama, and for professional groups (e.g. meteorologists) interested in understanding the impact of oil spills on coastal ecosystems.

Program Director:
Bruce Hamilton
CBET Program Director - Environmental Sustainability
NSF Award Number:   1042743
Award Title:   RAPID: Accelerating Biodegradation of Hydrocarbons from the Deepwater Horizon Oil Spill in the Gulf of Mexico with Naturally Occurring Marine Substrates
Principal Investigator:   Behzad Mortazavi
Institution Name:   University of Alabama Tuscaloosa
Program Element Code:   7643
CBET Research Highlight:   Fiscal Year 2012
Approved by CBET on:   27 March 2012

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This Award Achievement was Updated on 24 April 2012.